very simple c programming, pls help

using c programming language to develop a programm which can embed the message into a digital image.

a program has to read an image file (PPM or PGM only)from any source, then examine each pixel value in the image. the read pixel value should be presented in binary number. a message should be input by user, then program would convert the message (String) into binary value.

the right most binary value of each image pixel would be replaced by the string's binary number one by one!

Save the output.

if possible, display the result for user to view the changed image.

A reverse way have to perform, an embeded image is received, user open it with the c programming, then find out what the message is.

Hi, I would be able to create a windows interface using C#. I have worked on a program like this in the past and would have no problems developing and interface for you.
Hope to hear from you soon
Regards Damian